If they are the slow moulting type the flight feathers of wings will be replaced singly in each wing starting about time of summer solstice. As season progresses and weather gets really hot countour (hackle, saddle and body) will begin to be replaced as will be tail feathers. At some point usually about fall equinox feathers will in major turnover and many roosters will appear tailess. Another 60 days later all feathers will have been regrown.

Fast moulting types have a delayed start usually after it gets really hot and starts to cool down with respect to flight feathers of wings which are replaced in groups of 3 and moult will progress more rapidly to be completed roughly at same time as the slow moulting type. Such fast moulting birds often appear nealrly naked during moult.

You will have to determine which type of feather replacement system operates in your birds. This may be a function of breed. My games and most the American dominiques I have appear to be of the slow moulting types.

Make every effort to understand your chicken's biology and the environment that supports it.

Of course, the OP was asking if the age of molt varied by breed, not whether the birds were slow or fast molting. The age of the first big molt does not vary by breed. You can pretty much bank on it happening between 18-20 months of age and yes, some will take longer to go through it than others, though I haven't seen a breed difference here in the length of the molt in the breeds that we have here. I've had both fast molting Barred Rocks and slow molting Barred Rocks.

I have 4 RSL and 1 Dom that are just over a year old. When should I expect them to go through their first molt? Does it vary on different breeds?

Thanks

I had been wondering the same thing about molting-I have 4 Dominiques and 1 Black Australorp-they'll be a year on June 29th. So now with reading the replies and the average age being 18 to 20 months, I'm guessing they'll be pretty cold this winter as that will be when their big molt will begin.

Yeah that will put mine in Oct - Dec, lets hope that it happens in Oct. I would feel bad if they started to when it's below zero. Heck in MN that can happen in Oct. Should they stay in if they are molting and its below freezing out?

Well, if most of them are half-naked, yeah, keeping them inside in really frigid weather would be advisable. Chickens are great in the cold because feathers are great insulators, BUT if they have no feathers, that is a different story altogether.